Re: G5 powermacs

[Michael <macallan%netbsd.org@localhost>]

Hello,

On Sat, 10 Jun 2017 15:51:33 +0200 (CEST)
Havard Eidnes <he%NetBSD.org@localhost> wrote:

> >> Some things to try:  
> ...
> >> - in genfb.c, comment out the RI_8BIT_IS_RGB and RI_ENABLE_ALPHA flags.
> >>   This will prompt genfb to setup a traditional 16 colour ANSI palette
> >>   instead of an R3G3B2 one suitable for anti-aliased fonts. The colours
> >>   may look wrong ( since we inherit whatever OF set up ), but should be
> >>   readable.  
> 
> I've now tried that as well, and it produced the same result as
> the previous version: screen goes all-black, video signal is
> still there, but nothing is visible.  The difff I tried with is
> attached.

Hmm, so something goes wrong there, which is weird since on macppc we
scribble into video memory from the beginning ( wsdisplay_cnattach()
before even printing the kernel copyright ). IIRC ofb has code to remap
video memory with the G bit cleared ( to allow out of order writes and
write combining, which speeds things up ) via BAT, which the ppc970
doesn't have - I doubt it knows that, it hasn't been touched in ages.
So, to see how far we actually get, you could leave out both genfb and
ofb. This will leave you with the early kernel console, which may or
may not work properly later on, but should at least show how far we'd
get otherwise.

have fun
Michael